Perl 相当于(Postgre)SQL BETWEEN 运算符? [英] Perl equivalent of (Postgre)SQL BETWEEN operator?

问题描述

有这种事吗?a <= expr <= b 的等价物，或在 SQL 语言中的 expr BETWEEN a AND b，其中 expr 只计算一次?或者只是变得愚蠢?

Is there such a thing? The equivalent of a <= expr <= b, or in SQL parlance expr BETWEEN a AND b, where expr is evaluated only once? Or is asking for this just getting silly?

推荐答案

在 Perl 中有多种方法可以做到这一点.

There are a variety of ways to do that in Perl.

if( $a < $x and $x < $b ){ ... }
... if $a < $x and $x < $b;

use 5.10.1;
if( $x ~~ [$a..$b] ){ ... }

given( $x ){
  when( [$a..$b] ){ ... }
}

use 5.11.0; # development branch
given( $x ){
  ... when [$a..$b];
}

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